1. Field of the Invention
This invention relates, generally, to the medical arts. More particularly, it relates to an improved marker for marking the location of a lesion in soft tissue in biopsy procedures.
2. Description of the Prior Art
If a mammogram or similar means detects a lesion in soft tissue such as breast tissue, a biopsy must be performed to determine whether or not the lesion is benign or malignant. If benign, no surgical removal thereof is required.
One or more markers to indicate the location of the lesion are left in the breast tissue at the time the biopsy is performed, in the event surgery is needed. Although many different types of markers have been used over the years, a marker now in widespread use is a small metallic member that can be seen under X-rays. If the lab tests indicate that the lesion is malignant, the physician performing the surgical removal of the lesion removes the marker or markers at the same time the lesion is removed.
However, in about eighty percent (80%) of all cases where a biopsy is performed, the lesion is determined to be harmless and no surgical removal thereof is required. The patient is relieved to learn that no surgery is required, but unhappy when advised by the physician that the metallic marker or markers will remain in the breast tissue forever.
Unfortunately, the markers do not always remain in the breast tissue forever. They can migrate to the liver, the heart, the brain, or elsewhere, and cause problems. Surgery may then be needed to remove them. As patients learn about these complications from their physicians or others who have undergone biopsies, they are less inclined to request mammograms.
What is needed, then, is an improved marker for use in biopsies. The marker should be radiopaque so that it is visible under X-rays and/or ultrasound. Moreover, it should be less likely to migrate within the body, and it should never require surgical removal.
However, in view of the prior art, considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the medical arts how such a marker could be provided.
The long-standing but heretofore unfulfilled need for a biopsy marker that is less likely to migrate within the body and that requires no surgical removal is now fulfilled by a new, useful, and nonobvious invention.
The novel method for delivering markers that indicate the location of a lesion in soft tissue includes the steps of providing an elongate, flexible outer sheath of generally tubular configuration, providing an elongate, flexible marker carrier that is slideably received within the outer sheath, forming at least one marker retaining means in the marker carrier and positioning at least one marker in the at least one marker retaining means. The outer sheath and marker carrier ensleeved therewithin are introduced into an open proximal end of a needle of a biopsy tool. The outer sheath is advanced until a distal free end thereof extends through a port formed in a distal end of the needle.
The marker carrier is then unsheathed by retracting the outer sheath with respect to the marker carrier. An ejecting means is provided for ejecting the at least one marker from the marker carrier when the outer sheath is retracted relative to the marker carrier.
In this way, the position of the lesion is denoted by the at least one marker.
The at least one marker is preferably provided in the form of a hollow or solid member of predetermined configuration. In a hollow embodiment, the interior is filled with a radiopaque material, and the walls of the hollow marker are formed of a bioabsorbable material. A solid marker may be formed by pre-mixing a radiopaque material and a bioabsorbable material. In both hollow and solid embodiments, a dye or a radioactive material may replace or be used in conjunction with the radiopaque material.
In a preferred embodiment, the at least one marker is flexible, resilient and under compression when the marker carrier is ensheathed within the outer sheath. Accordingly, the means for ejecting the at least one marker includes the inherent bias of the at least one marker when the outer sheath is retracted relative to the marker carrier.
The marker carrier preferably has a recess of predetermined depth formed in an outer surface thereof for holding the at least one marker. The outer sheath has an internal diameter slightly greater than an external diameter of the marker carrier, and the at least one marker has a predetermined thickness that exceeds the predetermined depth of the recess so that the at least one marker is under compression when the marker carrier is ensleeved within the outer sheath. In this way, the at least one marker is ejected from the recess under its inherent bias when the outer sheath is withdrawn relative to the marker carrier.
In those embodiments where the at least one marker does not eject itself from the marker carrier upon unsheathing thereof, numerous other alternative ejection means may be employed. In one embodiment of an alternative ejection means, a push rod is slideably disposed within the marker carrier. The push rod has an exterior diameter slightly less than an interior diameter of the marker carrier. The at least one marker has a radially innermost side that is positioned within the interior bore of the marker carrier so that slideably introducing the push rod into the interior bore of the marker carrier displaces the at least one marker out of its marker retaining means so that the at least one marker is deployed into the soft tissue and remains in the soft tissue when the marker carrier is withdrawn from the soft tissue.
It is an important object of the present invention to provide a marker that is less likely to migrate any substantial distance within the body vis a vis conventional markers.
Another major object is to provide a marker that never requires surgical removal.
An object closely related to the foregoing object is to provide a marker that is bioabsorbable and which therefore disappears completely from the body, leaving no trace.
Another significant object is to provide an implement for deploying markers that can be used in conjunction with industry standard biopsy devices.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.